Synthesis of Novel Tylophorine Derivatives and Evaluation of Their Anti-Inflammatory Activity

We have previously demonstrated that DCB-3503, a tylophorine analogue, has an anti-inflammatory property in murine models for autoimmune diseases. However, its mechanism remains unknown. Here, we have synthesized 34 derivatives of DCB-3503 and investigated their effects on T cells differentiation and TNF-α production. Six derivatives (4, 9, 13, 19, 31, and 32) could significantly promote the expression of Foxp3. Among these, the IC50 of 31 and 32 was about 500 μM. Eight analogues (1, 2, 4, 9, 12, 18, 19, and 21) showed anti-TNF-α effect in Raw 264.7 cells and murine splenocytes, of which 18 and 19 were most significant. Moreover, 31 and 18 showed a better activity and cell survival ratio when compared with DCB-3503 at various concentrations. In summary, we have demonstrated the anti-inflammatory characteristics of 34 novel tylophorine derivatives and discussed their structure–activity relationship in order to explore their therapeutic potentials for inflammatory diseases.